The present invention provides a life jacket. In an embodiment, the life jacket includes a jacket member, and an air blowing member which is provided in the jacket member to inject air to the jacket member, wherein the air blowing member includes a base part coupled with the jacket member, and a tube part extending from the base part, wherein a flexible portion is formed in a part or the entire of the tube part.

A process of constructing an air tight and water tight seam, comprising cutting a sheet of selected material into two or more panels, sealing the panels at respective selected edges using an ultrasonic machine to form a seam, overlaying the seam with a tape made of the same selected material, and sealing the tape and seam using a radio frequency (RF) welding machine.